This application discloses three forms of center sections which may be utilized in lieu of the center section of my above-noted prior patented perforation testing device. Each of the three forms herein disclosed may be utilized as a replacement for the corresponding component of my prior patented perforation testing device and may be used, to advantage, in certain instances within the perforation testing device. The structure and operation of the various components of the oil well perforation testing device disclosed in my above pending application, as well as the prior art of record therein are included herein by reference thereto.